About 10% of what you need ...
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Asparagus has about 7.5 mg of vitamin C in it per serving. The RDA is between 65-90.
This makes asparagus a good source of Vitamin C but not an overly very high one. You would need to eat approximately 10 cups of asparagus each and every day to reach the amount of vitamin C that you require.
Vitamin C is usually found in foods such as red and green bell peppers, berries, broccoli and citrus fruit like oranges. You can generally get your entire RDA by eating one serving of one of those foods.
Some people like the idea of consuming vitamin C supplements. This is only really necessary if your diet is poor. Eating just a few of the healthy foods mentioned above a few times per week is generally good enough.
Asparagus is a good source of vitamin C but if you're looking to increase your vitamin C intake then asparagus wouldn't be your first choice. That shouldn't discourage you from eating asparagus as it has a lot of other health benefits.
Eat and enjoy nonetheless.
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